This invention relates to the field of head suspended ear covering apparatus usable for both protection against high intensity ambient noise and two-way communications with the protected user subject.
Persons obligated to work in high ambient noise environments have been known to incur premature hearing loss and other medically abnormal conditions. The metal fabrication industries, certain construction work, sawmill operation, riveting, and certain types of mineral mining provide notable historic examples of work environments in which hearing loss has resulted from prolonged exposure to impact and other high-energy noises. In more recent times, persons working in close proximity to running aircraft engines, in electrical power generation plants, and as crew members in the gunnery turrets of naval vessels and armored tanks, may be exposed to undesirable levels of sound energy and, without the use of protection equipment, become susceptible to noise-induced physiological problems. In relatively recent times, the advent of occupational safety and health administrations (OSHA) at both the federal and state government levels, has increased the awareness and knowledge needed in preventing prolonged exposure to undesirable ambient noise. The OSHA espoused rules relating noise exposure time inversely with noise intensity have been particularly effective in reducing the incidence of work-related hearing difficulties.
This new awareness, together with worker preference for convenient, lightweight and reliable hearing protection apparatus and the inherent requirement for a protected worker to communicate with other persons in his environment, has created a need for improvements in the hearing protection/communications equipment art. An opportunity for well-considered, simple and rugged equipment of this type is clearly illustrated by the working environment of a military ground crew member in the aircraft maintenance or arrival and departure operations of a U.S. Air Force base.
In this environment there is often a requirement for a ground crew member, positioned on the outside of an aircraft with a running engine to have the benefit of both ear-defending ambient noise protection and communication with the pilot or other crew-members stationed inside the fuselage of the aircraft. In a slight variation of this scenario, a ground crew member can expect to need hearing protection without needing to converse with the aircraft crew. Such needs often occur where the aircraft of interest is in motion or where ear protection is needed from the sound generated by adjacent aircraft, or where power tools such as air driven drills or racheting devices, must be used in the confined spaces of an aircraft. Sinoe the need transition from simple ear protection to ear protection combined with communications capability can be expected to occur frequently and on short notice in the activites of ground crew personnel. it is desirable to provide such persons with a single piece of headset equipment that is capab1e of performing both the ear protecting and communications functions with reasonable efficiency. In the interest of assuring optimum ear protection and desirable headband characteristics as are discussed below herein, the preferred equipment for such usage is in the nature of ear protection that is also provided with communications capability rather than communications apparatus that is used secondarily for ear protection.
In the Air Force ground crew environment, experience has shown that operating lifetime and ability to withstand hard usage are especially demanding additional requirements for headset equipment. In the ground crew work environment, hostile events in the nature of inclement weather conditions, headset droppage or other physical abuse, atmospheric dust and dirt and intense subjection to human body by-products such as moisture, salt, and organic oils, are expected headset operating life considerations. The prospect of droppage and other physical abuses is particularly great for equipment of this type. Such physical abuse and the other hostile conditions encountered frequently impose repeated repair requirements and general unreliability as expected attendants of using heretofore available headset equipment.